Approach/Methodology of Real Time Flood Forecasting-
Maharashtra state(World Bank Aided, India Hydrology Project Phase II)
Maharashtra (SW)Chief Engineer, Planning and Hydrology, Nashik
Krishna basin
Tapi basin
Godavari basin
West FlowingRivers Basin
Narmada basin
Flood Prone Areas in Maharashtra• About 7% area of Maharashtra state is flood prone:• 1. Mumbai (Mithi river) and Thane Metropolitan cities (July 2005)
• 2.Konkan Region - Vashisthi river (Chiplun), Savitri river (Mahad 1923,1976,1989,1994)), Amba river (Nagothane, Pen), Ulhas river
• 3. Krishna basin- Krishna, Panchganga, Warna (Sangli and Kolhapur 2005, 2006), Mula, Mutha (Pune), Bhima (Pandharpur 2006).
• 4. Godavari Basin- Godavari river (Nanded 1962, 1969, 1973, 1975, 2005), Wainganga (Bhandara district 2006 and Brahmapuri taluka (Chandrapur ), Conflulence of Wardha and Penganga (Chandrapur proper) (August 1979).
• 5. Tapi basin- Tapi (Jalgaon district)
• The Krishna and Bhima sub basins experience highly variable rainfall both in space and time ranging from 6000 mm in upper catchments to 400 mm in rain shadow areas (lower catchments).
• The state experiences flash floods particularly in Western
Ghats including Krishna and upper Bhima basins. For instance, Sangli, Kolhapur districts in Krishna basin and Pune, Solapur districts in Bhima basin experienced severe floods several times during recent decade (Year 2005 and 2006).
• Floods have caused heavy damages to the assets and loss of life.
Rainfall and Floods in Krishna basin
District
Crops & Infrastructure Land/ Structure
Damages
Horticulture
Total
Farmers SAU's Crops Govt. Nursery
Satara 329.3 2.3 63.7 152.9 0.5 548.7
Sangli 744.4 3.5 148.2 98.6 0.4 995.1
Kolhapur 2080.5 26.8 125.7 152.0 1.3 2386.3
DistrictHuman Losses Cattle Losses
2005 2006 2005 2006
Satara 11 23 156 239
Sangli 13 19 224 23
Kolhapur 26 26 236 80
Losses in flood 2005 (Rs.in Million)
Losses due to floods in Krishna River Basin
Human & Cattle losses in flood 2005 & 2006
Panchganga River Flood 2005
RESERVOIR OPERATION IN MAHARASHTRA
• The reservoirs in Maharashtra are multipurpose including hydropower, irrigation, domestic and industrial uses.
• Though these reservoirs are not specifically provided with flood cushion, they have moderated flood peaks to considerable extent by proper reservoir operations.
• Reservoirs are operated with rigid schedules as single entities based on the historical hydro-meteorological data and experience gained.
• These methods are often not adequate for establishing optimal operational decisions, especially where integrated operation of multiple reservoirs for flood management is contemplated.
• In addition, manual data observation and transmission results in a considerable time lag, between data observed in field and its communication to decision making level which sometime leaves little time, for flood forecasts.
• The Govt. of Maharashtra Vide Resolution dated 04/01/2007 constituted technical committee having main task of providing guidance for precise determination of reservoir releases during emergency situation in the state.
• The committee submitted the report in May 2007 by recommending Integrated Reservoir Operation, Basin Simulation and Real Time Flood Forecasting.
• To start with, for basin simulation study of Krishna sub basin, one division (Basin
Simulation Division, Pune) engaged and to supplement study with Real time data acquisition system, subject was included in the Mid Term Review of World Bank aided India Hydrology Project Phase-II, during October 1-14, 2009, (RTDSS: Maharashtra) as a new component.
• The RTDSS: Maharashtra includes both Krishna and Bhima sub basins in Maharashtra.
Recommendation of Technical Committee and RTDSS Maharashtra
Real time streamflow forecasting and reservoir operation system
14
INSAT Satellite
Internet
Decision Support Center
1. Real Time Data Acquisition System
The system would facilitate reservoir operators to act on time and prepare stakeholders for the floods.
The forecast of river flow and mapping of flood zone will help in taking the decisions such as evacuation of the areas likely to be affected well in advance.
In addition, the reservoir operation system would facilitate the optimization of the storages for ensuring flood cushion and improving agricultural productivity.
This system would revolutionize hydrologic monitoring system in the Krishna basin which will be extended to other basins later on.
Planned Benefits of the System
Planning and finalization of network:
1. Prepare inception proposal for each component with necessity of the work based on authentic information source defining problems in the area, objective of proposed work with scope, break up of activities into distinct groups with cost estimates. Two basic components will be i. Real time data acquisition system ii. Real time stream flow forecasting and integrated reservoir operation system.
2. Apart from this; provisions for River cross section survey works, site preparation and repairs to existing setups required for installation of RTDAS, Data collection and processing etc. may be done separately. Preparation of layout of the stations in line with the guide lines of IMD, WMO, CWC etc.
3. RTDAS Network Finalization: Finalization of category of stations, investigation, information collection, processing, sensor placements, communication mode finalization and arranging it in organized manner as a schedule of requirement.
• Station categories: Rainfall(ARS), River gauging (ARWL & RDS), Reservoir(ARWL & ODS), climate (AFCS), Canal gauging (ACWL& CDS)
• Check list prepared for information collection can be sent to different authorities(Divisions under regional CE’s in the basin) to collect data for each category of station and used in the finalization of schedule of requirements.
• Identify stations operated by co-operator agencies viz. IMD, CWC, ISRO, Agri. Dept etc. and are in operation.
a) Rain fall stations: Identify major and medium projects in the basin with compilation of their catchment area. Based on WMO, IMD, norms finalize required no. of stations. Finalize the locations to ensure that catchments are represented adequately facilitating drawing of Theissen polygon, avoiding too acute(<30 degree) and obtuse (>120 degree) angles.
i) Due consideration for local topography may be given. First priority must be up gradation of existing stations so that solution to land availability and security aspect is easier. Site selection shall follow IMD/WMO norms of exposure conditions.
ii)Network in free catchment may be finalized by integrating it with climate stations (Rainfall is one of parameter measured at AFCS).
iii)Existing civil works viz. available rooms, fencing, if are better can be utilized to reduce cost of civil work.
iv) Rainfall stations planned to be installed at dam sites can be combined either with reservoir stations or canal sites if distance is less than @ 300 m and line of sight is clear.
v) For area not represented by existing network new stations are to be proposed.
b)Reservoir station: Water level can be measured with Radar, Shaft Encoder or Bubbler type of sensors. Spillway discharge can be measured with provision of gate sensor for each gate (measures gate opening) and computation of discharge by formula.
If well up to MDDL is available Shaft encoder is best, if masonry/concrete upright wall of dam near gorge portion is available Radar is good choice. However in case of earthen dam with saddle spillway and bed level at spillway portion is much above MDDL and no availability of well, Bubbler is an option (canal intake well from outside can be used, approach channel to canal intake are deeper portions). Intakes or well with gates and other moving parts inside it etc. are not useful for sensor installation. From emergency situations point of view more reliable and uninterrupted communication is necessary for dam sites. VSAT supports two way communication and if SCADA is on future agenda, VSAT is a good option for dams.
c)River gauging sites: The guidelines specified by CWC, manuals provided in HPI needs to be followed. i) identify critical flood pone area, important cities/towns in the basin and study the existing network. Ii) Reservoirs with gate sensor arrangement also acts as a gauging site. iii) However if rivers are too long, tributaries carrying large floods are joining the main river and important towns/localities needs early warning; river gauging sites can be proposed at u/s of city or on tributaries near confluence and on main river downstream.
iv) Important barrages along the rivers also can be provided with water level sensor. v) Existing forecast points finalized by Valley corporations/CWC may be included on priority. vi) Availability of stage discharge curves at river gauging sites is a important requirement.
vi)Communication: Mostly stations in the catchment do not have enough mobile signal strength and can be placed on VSAT/INSAT. For free catchment stations GSM can be used. Also in future if SCADA is to be implemented VSAT seems to be a good choice as it supports two way communication.
The planned network were discussed with River basin authority for its suitability for the purposes.
ABSTRACT of proposed RTDAS Network
Basin Name
Rain Gauge StationsRiver Water Level
(Stage) & River Discharge
Reservoir Water Level & Outflow
Discharges FCS Remark
Krishna
Within Catchment (37)
In free Catchment (30)
13 + 1 CWC 14 + 9 AWS
Existing Proposed Existing Proposed Existing Proposed Proposed Existing Proposed
25 12 26 4 10 3 19 7 7
Bhima
Rain Gauge Stations River Water Level
(Stage) & River Discharge
Reservoir Water Level & Outflow
DischargesFCS
Within Catchment In free Catchment 18 + 2 CWC 26 + 20 AWS
Existing Proposed Existing Proposed Existing Proposed Proposed Existing Proposed
22 35 19 6 14 4 27 12 14
Total =67 + 82 = 149= (13 + 18) + (1 + 2) CWC = 31 + 3 CWC
= 19 + 27 = 46= (14 + 26) + (9 + 20) AWS = 40 + 29
AWS
Final tally 149 31 + 3 CWC 46 40 + 29 AWS 298
RTDAS network Installed
Sr No Description
Proposed number of stations
Commissioned stations Balance stations
1 Automated Rainfall Stations 127 127 00
2 Automated Full Climate Stations 39 39 00
3 Automated River water Level and River Discharge Stations 31 31 00
4Automated River water Level and River Discharge Stations combined with Automated Rainfall Stations
03 03 00
5Automated River water Level and River Discharge Stations combined with Automated Full Climate Stations
03 03 00
6 Automated Reservoir water Level and outflow Discharge Stations 27 26 01
7Automated Reservoir water Level and outflow Discharge Stations combined with Automated Rainfall Stations
19 19 00
Total 249 248 01
Data AvailabilityHydro meteorological data:Rainfall data : SRG (twice daily)and ARG (hourly): Source- HP(SW), Reservoir
Management wing of WRD, IMD, ISRO.Climate data: Dry & wet bulb temp (to know RH), max and min temp, wind
speed(Average and instantaneous), wind direction, pan evaporation, rainfall, solar radiation: FCS (twice daily): Source- HP(SW), IMD,ISRO
River gauging data: stage (twice daily/hourly) and discharge (twice daily); stage discharge curves, zero gauge, HFL, type of station(bridge outfit/winch & cableway/wading). AWLR condition Source- HP(SW), CWC
Reservoir data: dam type, salient features, various control levels, area capacity elevation curves, time series data of inflow, spillway discharge, evaporation, releases for different uses (irrigation, hydropower, drinking/industrial demands) , guide rules, rule curves, spillway type, No. and types of spillway gates, discharge tables for spillway gates etc: Management wing of WRD.
• River Cross section data: Spatial interval @ 500 m to 1 km: Only @ 5 % of cross sections required were available. Source- Management wing of WRD. Physical survey was carried out in two working season.
• Latitude, longitude of all stations planned are verified with hand held GPS. Check list for all category of stations were prepared and was circulated for field offices to know site situation and were analyzed and organized for bidding document.
• Computerized and well organized data of rainfall, climate station was available. Computerized Reservoir/Tank data was made available by SE, KWDT Office at Pune. However few reservoirs data manuscript were available and needed computerization. Fitting Rating curves for river gauging sites was imp. Task. Spillway rating curves, area elevation capacity curve, Rule curves, spillway gate discharge table needed computerization.
• DEM, Satellite imageries, GIS layers were used by Consultants.
Installations under RTDASAutomated Rainfall Stations :1) Thoseghar 2) Pabal
Automated River Water Level (Stage) and Discharge Stations: 1) Kalyani Nagar bridge 2) Pimple Gurav
Automated Full Climate Stations : 1)Bhima nagar 2) Rosa
Automated Reservoir Water Level and Outflow discharge stations: 1)Kadvi 2) Radhanagari
Automated Reservoir Water Level and Outflow discharge station :1)Dhom Balkawadi (Bubbler) 2) Urmodi (Shaft Encoder)
ADCP Measurement : Pimple Gurav river gauging site
Pimpale Gurav_GD1.pdf
Discharge Measurement using ADCP in Krishna & Bhima Basin
Cost of Main component of RTDSS
• Administrative approval cost: Rs. 3033 lakhs; Expenditure: @ 2900 lakhs• Technical consultancy for Implementation of RTSF and ROS for Krishna
and Bhima basins• Consultants: DHI(India), Water and Environment Pvt. Ltd, India• ICB Tender Cost: Rs. 762.39 Lakhs (Note: Service tax @12.36% to be
added separately, Payments are based on Euro exchange rates which varied from 62 to 84 during contract operation period); Contract Period: 42 months (18 months for main task and 24 months support period).
• Supply, Installation, Testing, Commissioning and Maintenance of RTDAS for Krishna Bhima basins of Maharashtra
• Contractor: Mechatronis Systems Pvt.Ltd., Pune• ICB Tender Cost: Rs. 1790.07 Lakhs (One year warranty period cost
included; VAT @ 8% and Service Taxes 12.36% extra); Contract Period: 18 months; One year warranty Period, 4 year Post warranty period.
• River cross section survey work: @ Rs. 68 lakhs• Electrification , Environmental control of data center, furniture etc: 12
lakhs• WSR repairs for installation of Shaft encoders: @ 7 lakhs
Important Issues
• Sufficient and qualified, trained staff not available
• Liability of HPII- 1.60 Crore• Four year Operation and Maintenance
contract- budget availability• Support of DHI is necessary even after support
period (ending by FEB 2015)
Modelling the hydrological system(Rainfall Runoff Model)
Time Delay
Time Delay
Time Delay
Time Delay
NOW!
Future!
SOIL MOISTURE PROFILE
Depth
L
Lmax
GWL
Sy
GWL
GROUNDWATER STORAGE
Root Zone
GWPump
BF
BaseFlow
GWLBFo
CKBF
LOVER ZONE STORAGELmax
L
BFu
DL
CAFlux
SURFACE STORAGE UUmax
OF
IF
G
RAIN
SNOW
SNOW STORAGE
PPs
QIF
InterFlow
Pn
CK1
CK2
QOF
Overland Flow
Ep
Ea
Owp Ofc Osat
SOIL MOISTURE PROFILE
Depth
L
Lmax
GWL
Sy
GWL
GROUNDWATER STORAGE
Root Zone
GWPump
BF
BaseFlow
GWLBFo
CKBF
LOVER ZONE STORAGELmax
L
BFu
DL
CAFlux
SURFACE STORAGE UUmax
OF
IF
G
RAIN
SNOW
SNOW STORAGE
PPs
QIF
InterFlow
Pn
CK1
CK2
QOF
Overland Flow
Ep
Ea
Owp Ofc Osat
The Hydrological Model(Conceptual catchment Model)
• Coutinuous Moisture Accounting model such as NAM holds a memory of the catchment history
Memory of past days of rainfall in the Soil Storages, distributed over the basin
Memory of past monsoon rainfall in the groundwater storage, distributed over the Basin
Rainfall – runoff model
A Basin is divided into a large number of sub-catchment and Computed Catchment runoff are routed through the
river network
Example of perfect calibration (Koyna)
Comparison of Simulated and Observed Discharges for Koyna Catchment (R2=0.95, Wbl=0.00% (Obs=5660mm/y, Sim=5660mm/y))
Simple Inflow forecasting (CWC)
With knowledge on conditions upstream, downstream flows can be estimated
U/S Station
D/S Station
Hydrological Modelling, How does it help in Inflow forecasting?
Hydrological modelling helps quantifying the reservoir inflows
Rainfall(current and future – QPF)
Basin wise water resources simulation model
MIKE BASIN MODEL (applied in the DSS- Planning Project, HP-II)
Krishna-Bhima MIKEBASIN Model
Hydrodynamic model for flood forecast :Introduction to MIKE 11
MIKE 11 is a world standard in 1D river modelling for simulating flow and water level, water quality and sediment transport in rivers, floodplains, irrigation canals, reservoirs and other inland water bodies.
PHYSICAL SYSTEMRiver Network
FloodplainsStructures
PHYSICAL LAWSConservation of Mass
Conservation of Momentum
SCHEMATISERepresent by a simple
Equivalent System
DISCRETISEExpress as a Finite Difference Relation
NUMERICAL MODEL
Modelling of unsteady flow is based on three fundamental elements:
• A differential relationship expressing the physical laws
• A finite difference scheme producing a system of algebraic equations
• A mathematical algorithm to solve these equations
HYDRODYNAMICS
The MIKE 11 Hydrodynamic Module
Saint Venant Equations
6 Point Abbott-Ionescu Finite Difference Schemedynamic/diffusive/kinematic
Looped Network
Q
x
h
t
Q
t
QA
x
h
x + b = 0, + + gA = 0
2
Databases
•Topographical Data
•Time Series DataWater Quality
Sediment Transport
Hydrodynamics
Rainfall-Runoff
Advection-Dispersion
Flood Forecasting
Modules and Databases that Interact Dynamically
ArcGIS
Pre- and Post- Processing
MIKE11 STRUCTURE
Reservoirs & Hydraulic StructuresWide Range of Structures Requested – and Available in MIKE 11
The Bhima-Krishna Network
Hydrodynamic model calibration
Sequence of Steps in Forecasting System1.Import data from RTDAS
2.Import data from Pune Flood Control www.punefloodcontrol.com
3.Import QPF – Quantitative Precipitation Forecast
4.Mike 11 Simulation
5.Results in .dfs0 files
6.Prepare Results for WEB Page
7.Archival of Results
8.Uploading Forecast to Web Saving Forecast in KBS
http://www.rtsfros.com/mahakrishna
(Real time data and forecast of water level and discharge can be viewed on this website)
WEB Portal of RTSF&ROS
Model Outputs (Flood maps)
Simulated flood map of Pandarpur for a high discharge of 325,000 cusecs)
Scenario - Reservoirs
68
STATISTICAL ANALYSIS OF RESERVOIR WATER LEVEL
Comparision of Model Predicted Releases from Reservoir and Actual Releases (Outflow) : Krishna Reservoirs
Comparison of Forecasted Water Level and Water Level by Sensor for Reservoir (One Day Forecast)
Comparison of Forecasted Water Level and Water Level by Sensor for Reservoirs (One Day Forecast)-July 2013
Reservoir Water Level Comparison ( Sensor & RTSF Model): July 2014
River Discharge Comparison ( RTDAS level and derived from G-D curve & RTSF Model)
River Water Level Comparison ( Sensor & RTSF Model): July 2014
Travel time computation
75
Indicative Area For LiDAR Survey for Sangli
THANK YOU
Top Related